A Gasoline-Powered Stock Market

Friday saw a 12-ton, 76-foot Norway spruce ride into New York City to be decorated and displayed in Rockefeller Plaza, just in front of my office. The holiday season officially kicked off.

Holidays may prove extra cheery this year, at least in the United States, thanks to something a lot less visible than New York City's giant tree: gasoline prices. Recent days have seen the national average gasoline price approach its lowest level...